The object is a 3.5mm audio splitter, which allows two sets of headphones to be connected to one device. Here's some additional information:
It features a 3.5mm male jack on one end and two 3.5mm female jacks on the other.
It enables sharing audio with another person.
It is compatible with devices that have a 3.5mm headphone jack.
Some models come with a keychain for portability.
It does not support microphone input for phone calls.
Ou coud connct upto 2 ouputs. Even if you are travelling and you have 2 sets of earphines, you could watch movie or listen to music using one phone.